Aooni the Blue Monster

A mansion away from the village, which no one lives, is rumored to have a ghost appearing. Hiroshi visits the mansion with his classmates Takurou, Takeshi, and Mika, and gets attacked by a mysterious creature named Ao Oni. Will they be able to get out of the mansion while solving various puzzles, or... will they become crazy and just live in this mansion with an Ao Oni like that?! The daring lives of the four being played by Ao Oni starts now.